Phase synchronization of baroreflex oscillations of blood pressure and pulse interval in rats: the effects of cardiac autonomic blockade and gradual blood lossстатьяЭлектронная публикация
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Дата последнего поиска статьи во внешних источниках: 17 июля 2019 г.
Аннотация:OBJECTIVE: Phase synchronization of arterial pressure (AP) and pulse interval (PI) oscillations in the low-frequency band (around 0.4 Hz in rats) is governed by baroreflex activity. In long-term stationary data recordings, such synchronization can be estimated by the coherence. Phase synchronization index (PSI) can be used as well. The aim of this study was to correlate PSI and the coherence of AP and PI under stationary conditions and to estimate the informativity of PSI as a measure of baroreflex activity during transient processes.
APPROACH: AP and PI were recorded in conscious Wistar rats through femoral artery catheter. To study the hemodynamics during hemorrhage, blood was gradually withdrawn (20 ml*kg-1 during 30 min) through a catheter in carotid artery.
MAIN RESULTS: PSI and coherence spectra calculated from 30-min-long AP and PI recordings demonstrated distinct peaks at the frequency of 0.4 Hz; these indicators correlate well with each other (Pearson r = 0.920, p <0.0001). Both PSI and coherence were markedly suppressed by vagal blockade (methylatropine) and tended to reduce after sympathetic blockade (atenolol). Importantly, PSI demonstrated dynamic alterations during gradual hemorrhage. During initial approx. 10 min of hemorrhage, AP did not change but PI was noticeably shortened, and PSI increased, which indicates the activation of the baroreflex. With further blood loss, baroreflex influences were not enough to prevent blood pressure fall, under such conditions PSI decreased.
SIGNIFICANCE: PSI, like coherence, is an informative measure of baroreflex activity under stationary conditions. Along with that, PSI permits to follow the coupling between baroreflex oscillations of AP and PI during transient processes which strengthen its informative value.